Electrical tilt mean that you can change the phase shifter between the antenna dipole inside it to provide different antenna patterns depending on how many degrees you changed,, in other words, the density of radio waves will decreased

As shown in above photos in electrical tilt case, the radio waves reduced in all directions ( you can say you pull the density) and also the back loop will be down as main loop . The mechanical tilt is to make physical tilt if the antenna budy to be down without changing the antenna patterns.

I mean the antenna patterns not changed when it outgoing from the antenna to the air,,, but instead of this waves can gi to 2 km for example, it will go down ti 1k meters instead with same constructed density

You can see in above photos that side loop in mechanical tilt not changed,, yes